Download Chapter 10 Notes - Deer Creek High School

Principles of Evolution: Chapter 10
Common Myths and Misconceptions
• “Evolution is just a theory”
• Evolution states that humans evolved from monkeys
• “I don’t believe in evolution”
• Religion and science/evolution are incompatible
• Evolution isn’t science because it’s not testable
• Survival of the fittest means only the biggest, strongest, or smartest
survive
• Evolution explains the origin of life
• We can evolve during our lifetimes
Evolution unites all fields of biology.
• Scientist from any fields contribute to the understanding
of evolution.
• The basic principles of evolution are used in many
scientific fields.
Early scientists proposed ideas about
evolution.
• Evolution is the biological change process by which
descendants come to differ from their ancestors.
• A species is a group of organisms that can reproduce
and have fertile offspring.
• There were many important naturalists in the 18th century.
– Linnaeus: classification system from kingdom to species
– Buffon: species shared ancestors rather than arising
separately
– E. Darwin: more-complex forms developed from lesscomplex forms
– Lamarck: environmental change leads to use or disuse
of a structure
Darwin observed differences among island
species.
• Variation is a difference in a physical trait.
• Galápagos tortoises that live in areas with tall plants have long
necks and legs.
• Galápagos finches that live in areas with hard-shelled nuts
have strong beaks.
• An adaptations is a feature that allow an organism to
better survive in its environment.
– Species are able to adapt to their
environment.
– Adaptations can lead to genetic
change in a population.
Darwin observed fossil and geologic
evidence supporting an ancient Earth.
• Darwin found fossils of extinct animals that resemble
modern animals.
• Darwin found fossil shells high up in the Andes mountains.
Several key insights led to Darwin’s idea
for natural selection.
• Darwin noticed a lot of variation in domesticated
plants and animals.
• Artificial selection is the process by which humans
select traits through breeding.
neck feathers
crop
tail feathers
• Natural selection is a mechanism by which individuals
that have inherited beneficial adaptations produce
more offspring on average than do other individuals.
• Heritability is the ability of a trait to be passed down.
• There is a struggle for survival due to overpopulation
and limited resources.
• Darwin proposed that adaptations arose over many
generations.
Natural selection acts on existing variation.
• Natural selection can act only on traits that already exist.
• Structures take on new functions in addition to their
original function.
five digits
http://ed.ted.co
m/lessons/fivefingers-ofevolution
wrist bone
Evidence for evolution in Darwin’s time
came from several sources.
• Fossils provide evidence of evolution.
• Fossils in older layers are more primitive than
those in the upper layers.
Fossils provide a record of evolution.
• Paleontology is the study of fossils or extinct organisms.
• Paleontology provides evidence to support evolution.
Molecular and genetic evidence support
fossil and anatomical evidence.
• Two closely-related organisms will have similar DNA
sequences.
• Embryology provides evidence of evolution.
– identical larvae, different adult body forms
– similar embryos, diverse organisms
Larva
Adult crab
Adult barnacle
• The study of anatomy provides evidence of evolution.
– Homologous structures are similar in structure but
different in function.
– Homologous structures are evidence of a common
ancestor.
Human hand
Mole foot
Bat wing
• The study of anatomy provides evidence of evolution.
– Analogous structures have a similar function.
Human hand
foot
• Analogous structures are notMole
evidence
of a common ancestor.
Fly wing
Bat wing
Structural patterns are clues to the history
of a species.
• Vestigial structures are remnants of organs or structures
that had a function in an early ancestor.
• Ostrich wings are examples of vestigial structures.